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Five Misconceptions About the Role of Genomics in Public Health

Posted on July 13, 2016 by Muin J Khoury, Director, Office of Public Health Genomics, Centers for Disease Control and Prevention

In a recent post, I reviewed the progress of genomics in public health over the past two decades and pondered on the lingering skepticism about genomics in the public health community.

I propose that this skepticism is driven, at least in part, by 5 common misconceptions about the role of genomics in public health. In this post, I present each of these misconceptions and discuss the reasons why each is incorrect.

Collectively, these misconceptions impede progress in the integration of emerging genomic sciences into public health programs.

Misconception 1: Genomics is about rare diseases that have a small impact on public health.

As we discuss elsewhere, there are thousands of diseases that are individually rare but collectively common. In the United States, rare diseases affect about 25 million people. Most rare diseases have a genetic cause. Genome sequencing is now been applied with increasing success in the work-up of patients with rare diseases, ending years of diagnostic odysseys and contributing to management of patients and families. A comprehensive public health approach can actually improve health, empower patients, and reduce the population burden of disease and disability from rare diseases. Newborn screening, the largest public health program in the world that is focused on genetic and other rare diseases, is a prominent success story.

Misconception 2: Genetic factors are less important than environmental, behavioral, and social determinants of health.

Most human diseases involve complex interactions of genes and environmental and behavioral risk factors, such as diet, physical activity, infectious agents, and the physical environment. In spite of this, many consider genetic factors less important that environmental determinants of health, as we discussed in a previous post. For example, a 2014 CDC MMWR report on geographic differences in preventable deaths in the United States suggested that at least a third of deaths every year from the 5 leading causes of deaths are potentially preventable by reducing the prevalence of known risk factors. Press coverage overinterpreted results with statements like “Lifespan to do more with geography than genetics.” In fact, “both zip codes and genetic codes are important for our health.” The CDC report itself did not address genetic factors and acknowledged that “death rates are population health outcome measures that reflect the combined influences of multiple biological and social health determinants, public health efforts, and medical care.”

Misconception 3: Genetic factors are non-modifiable and therefore merit little or no attention when it comes to public health programs and communication strategies.

A common belief is that since genetic factors are non-modifiable, they do not merit extra attention when it comes to public health efforts in reducing morbidity and mortality. However, even non-modifiable risk factors such as age, race, and ethnicity are still used in targeting clinical and public health interventions (e.g. hepatitis C screening among baby boomers). A simple family health history can provide valuable information that can help identify people who are at higher risk for certain diseases and who need targeted medical or lifestyle interventions[PDF 138 KB] (e.g. prediabetes, heart disease, certain cancers). Family history is mentioned in several evidence-based guidelines for prevention.

Misconception 4: Genomics is about the future: the evidence for using genomic information is not sufficient for use in practice today.

A common argument is there is very little evidence of utility of genome-based information for behavior modification for lifestyle and other preventive interventions (e.g. smoking cessation, increased physical activity). Nevertheless, we have plenty of evidence that a genetically-targeted approach to health can save many lives. Our office has developed a 3-tiered evidence-based classification schema of genomic applications based on evidence for their use.

Tier 1 applications are those with sufficient evidence for clinical validity and clinical utility to provide meaningful and actionable information to consumers and providers. Tier 2 applications are those with established evidence of validity but insufficient evidence of utility to support a recommendation for use. Tier 3 applications are those with either sufficient evidence for a lack of utility or presence of clear risk for harms, or those with insufficient evidence for both validity and utility.

In addition to newborn screening and several genomic applications that can influence cancer treatment outcomes, there are several examples of tier 1 conditions for which genetic testing is recommended in healthy people at high genetic risk (e.g. hereditary breast and ovarian cancer, Lynch syndrome patients and familial hypercholesterolemia). An estimated 2 million people in the US have one of these 3 conditions and most are not aware of their risk. Once identified, there are evidence-based interventions that can significantly reduce morbidity and mortality from heart disease and cancer.

Misconception 5: Genomics is in the domain of health care, and thus there is no need for public health programs to be involved.

Finally, a common misconception is that genomics is about health care and public health has little, if any, role to play in its implementation. However, pathogen genome sequencing is used in public health programs to track infectious disease outbreak sources, spread, and susceptibility to antibiotics.CDC’s Advanced Molecular Detection Initiative is combining genomics, and bioinformatics and epidemiology, to enhance public health surveillance, investigations, and control of infectious diseases. In human genomics, public health and health care are collaborating to optimally implement validated genomic applications and to reduce health disparities. Cancer programs at the federal and state levels are increasingly responding to the challenge of cancer genomics as recently highlighted in the CDC Public Health Grand Rounds: “Cancer and Family History: Using Genomics for Prevention.” The session focused on public health activities in conducting surveillance of cancer genetic services, evaluating and promoting evidence-based policies, as well educating providers and the general public in cancer genetics.

To address these and possibly other misconceptions about the role of genomics in public health, our office continues to develop communication messages and training opportunities for the public health community. But there is so much more to do. We welcome hearing from our readers about tackling challenges and opportunities for using genomics to improve population health.

Posted on July 13, 2016 by Muin J Khoury, Director, Office of Public Health Genomics, Centers for Disease Control and Prevention